Creating a database, although not a task that you will undertake every day, is certainly a task that will be very important in your career as a DBA. It is something that will take thought and planning and something that you should understand early, both in your career and in your exam preparations. This chapter shows you how to create a database manually and use the GUI interface.

Creating a database is, naturally, the first step in managing a database. The database may be one created automatically as a part of the initial Oracle 9i Server installation, or it can be created later, either using the Database Configuration Assistant or manually with database creation scripts. If you are migrating a database from an earlier version (8i, for example), you can accomplish this either through the use of the database migration assistant or the use of migration scripts.

Database creation is the task of preparing several operating system files. It is a task needed only once for a database, regardless of how many data files that database ultimately has. Because of the importance of this task, careful decisions must be made on many of the database settings.

Prerequisites for Database Creation

To create a new database, you must have the following:

A privileged account authenticated either by the operating system or by
use of a password file.

Sufficient memory on the computer to allow the instance to start. This
needs to be large enough for the entire SGA, the Oracle executables, and the
processes supporting the instance.

Sufficient disk space for the planned database. Included in your
calculations needs to be the disk space that is necessary for the database, its
data files, the online redo log files (including the multiplexed files), and the
control files (including any multiplexed versions).

Sufficient disk space for archive logs for the planned database. Include
in your calculations sufficient disk space to store archived redo log files.
Although a data warehouse may not need to have archive logs for normal
operations, it is important to have them for a period of time to facilitate
recovery of the database.